Is there any real home/cheap remedies to fix CD's?
They sell polishers for $20-40 or so that work to a point if surface scratches are the issue. A record store or online source will be your best bet. Denatured, not isopropyl (has lanolin in it), alcohol and a soft cloth can get surface finger prints, and stuff off.
Some video rental places have commercial disc/cleaner polishers and even offer disc cleaning as a service.
There is probably a data restoration company or two listed in your phone book or you can find them online. Some of them really can do an amazing job of rescuing discs or even pieces of them but for a cost.
CDs were supposed to last a lifetime but it is not working out that way and some don't even last as long as old magnetic media. The plastics are failing and the metals corroding. Recordable CDs are the worst as the dyes the laser colors into zeros and ones are proving to not hold up well. Recordable DVD blanks are even worse. Commercial albums and movies with the 0's and 1's are hanging in there but again, the plastics and metals are failing.
As suggested, a good copy program should keep patiently trying to read data and eventually come up with something that can be burned to a new CD. With a polisher and smudges cleaned it MIGHT work to get you a working copy.
Make sure your laser lens is clean before attempting a restoration. If it is too dirty to read things you cannot hope for much.
Sorry not seem somewhat pessimistic. You may not be able to recover discs. A kid in my past life rendered gaming discs non-recoverable.